Force between magnet and metal

AI Thread Summary
Calculating the attractive force between a cylindrical magnet and a sheet of iron is complex, as standard equations for magnets do not directly apply to non-magnetized materials. The magnetic flux density (B) in the gap is crucial, typically approaching \mu_{0}M when the magnet is close to the iron. For precise force calculations involving arbitrary shapes and distances, one must determine the B distribution in the air gap and utilize the Maxwell stress tensor. Numerical methods are often required to achieve accurate results. Understanding these principles is essential for effective calculations in magnetism.
McSquirrel
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Hello,

I am trying to calculate the magnitude of the attractive force between a cylindrical magnet and a sheet of iron. A bit of searching found some equations that can be used to calculate the force between two magnets but I could not find anything related to magnetic force on non magnetized materials. I can't link them as this is my first post but searching wikipedia for "force between two magnets" will yield them.

Can you use a similar equation to find the force between a magnet and a metal?
 
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For nearby magnetized surfaces, the equation is given in the same Wiki page. But you need to calculate B in the gap between the two surfaces which usually requires numerical methods. When a magnet is brought very close to an iron sheet, the flux density B approaches \mu_{0}M where M is the magnetization density of the magnet which is constant.
For an accurate calculation of the force for arbitrary shape and distance, you need to find the B distribution in the air region and use Maxwell stress tensor to calculate the total force on the object. see this page: http://www.fieldp.com/documents/stresstensor.pdf
 
That is quite helpful. Thank you Hassan!
 
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